Compatible Transistors

[Dan Heal]

Hi guys,

Possibly a stupid question here, I have been through the old forums and only found reference to this on one post so I just wanted to confirm-

Can I use a MJ21194 transistor as opposed to MJL21194 Its just that they are half the price (a third of the price if you buy more than ten) on the RS website as compared to the MJL21194 transistors I previously purchased from Jaycar...

Maybe someone in the know could post any other known compatible transistors?

Thank you in advance!

Dan

[James Milner]

Dan, whilst I am not yet qualified enough to tell you what compatible resistors you can use I have found a good site to buy the MJL21194's. Futurlec. They have a number of websites including an Australian one. It turns out they shipped my product from their Asian warehouse but it only cost me $4.25 ea averaged over 20 including postage or just $3.90ea excluding postage. It took a couple of weeks but worth it. I got quite a few matched transistors in the 20 ordered. 1set of 5 and another set of 6 and 2 pairs.
I thought that was pretty good considering you would pay a lot to purchased matched components!
James

[Ren]

Hi guys,

Possibly a stupid question here, I have been through the old forums and only found reference to this on one post so I just wanted to confirm-

Can I use a MJ21194 transistor as opposed to MJL21194 Its just that they are half the price (a third of the price if you buy more than ten) on the RS website as compared to the MJL21194 transistors I previously purchased from Jaycar...

Maybe someone in the know could post any other known compatible transistors?

Thank you in advance!

Dan

Hi Dan,

Dont bother getting your MJLs from Jaycar, at $12 plus a pop you will be broke in short order. With our dollar doing well you should look at getting them from the states.

Please check this page out, Counterfeit Transistors It is possible that some of the really cheap ones are too good to be true as seen in the link.

MJ21194 looks to be the same as the MJL21194, just in a different packaging.

This store also offers MATCHED sets, up to 8. Tech DIY Company Store Pretty darn good IMO.

Regards

[Dan Heal]

I know what you mean about the counterfeit transistors Ren. This is why I have only bought from reputable sources and not ebay. Thanks for the replies, I will check them out.

[Gary Hammond]

I got mine from Newark. Their current pricing for Each MJL21194G from ON SEMICONDUCTOR is:

1+ $4.95
25+ $4.14
100+ $3.33
250+ $3.19

But I don't think they list any as being beta matched. You have to do that yourself.

[Dan Heal]

Whats the best way to test for them being matched? is one of those cheap multimeters with the function okay? Or maybe something like this-

Multi Use Transistor Tester Detector Meter * resistor capacitor * NPN PNP MOSFET | eBay

I just don't trust cheap meters, would it be accurate enough? My fluke doesn't have the function, no decent meters seem to...

[Gary Hammond]

Hi Dan,

I just got a PEAK - DCA55R - COMPONENT ANALYSER, SEMICONDUCTOR that I used to match mine. It measures the operating characteristics of most semiconductors. Seems to have pretty good repeatability. Here's a link to it
DCA55R - PEAK - COMPONENT ANALYSER, SEMICONDUCTOR | Newark

And here's a link to it's data sheet. http://www.peakelec.co.uk/downloads/...duct_brief.pdf

[GlenWV]

Greetings:

Newark offers a substitute: 2STC5200 from STMicroelectronics.
TRANSISTOR, NPN TO-264
Transistor Polarity: NPN
Collector Emitter Voltage V(br)ceo: 230V
Transition Frequency Typ ft: 30MHz
Power Dissipation Pd: 150W
DC Collector Current: 8A
DC Current Gain hFE: 80
Transistor Case Style: TO-264
RoHS Compliant: Yes

They come from the UK and shipping is a flat $20.00, so order plenty if you go this route.
I have some of these on a solid state machine and they seem to work ok.

On my 'real' machines, I still use the MJL's and generally get them from Mouser or on eBay.

glen

[Barrie Castle]

Guys,

The listed equivalent for the MJL21194 is the 2STC5200:

Formerly Farnell | Electronic Components Distributor | element14 Australia

I used one that my local store (no freight charges!), Aztronics, had in stock for $4 on my second SSG. Worked very well on my load test. "Over Unity" on 11 out of 21 runs. Last month, they were all sold out - not buying any more in.

[radiant]

I've have GREAT success with MOST H.O Transistors out of CRT televisions. BU2508AF, FJL6920, 2SC5588...FJL6920 is my favourite because it has a built in damping diode across the
C & E. I don't use neons anymore. Haven't blown one up yet...

My finding is that matched sets really make no difference to the charge time or COP...I would suggest you experiment for yourself to see if those things matter to your application.

I have devices which use a mixture of these these transistors and it works fine.

[Faraday88]

Hi Dan,

Try this device: MJL21194G its 250V , 16A DEVICE NPN.

Rgds,
Faraday88.

[Tom C]

I've have GREAT success with MOST H.O Transistors out of CRT televisions. BU2508AF, FJL6920, 2SC5588...FJL6920 is my favourite because it has a built in damping diode across the
C & E. I don't use neons anymore. Haven't blown one up yet...

My finding is that matched sets really make no difference to the charge time or COP...I would suggest you experiment for yourself to see if those things matter to your application.

I have devices which use a mixture of these these transistors and it works fine.

you match so that the circuit is tuned to itself, if you have unequal flow thru the base because of differences in the opening. its like telling an amp builder that base current does not matter, that it can be wherever you want. equal flow thru all branches is imperative. you get a big enough mismatch and you get a hot transistor and you blow things up. I hve noticed when all transistors and base resistors are matched. that at 12 volts you can unhook the charge battery and nothing blows up WITHOUT NEONS...........

it really does matter cause JB said so!



Tom C

[Faraday88]

Hi Tom C,
'you can unhook the charge battery and nothing blows up WITHOUT NEONS...........'

I belive in this situation the coils get conditioned to its Intrinsic and distirbuted Parameters (Inductance and Capacitance) which includes
the Switching Transistors. the tunning and matching to acheive this is indeed very difficut, i have had it happen accidently though couple of times in the far past .
Rgds,
Faraday88.

[radiant]

Can you show me the reference/context where JB said that?

[Tom C]

Can you show me the reference/context where JB said that?

I was standing at the bench in his shop watching him put his amps into class A mode, he said you have to match transistors in audio amps. takes an hour or so for each one to get into class A watching the meters and tweaking, tunes them by hand. I asked him if it was the same with the monopoles, he said "even more important"

Tom C